This invention relates to multi yarn machinery for producing fabric such as tufting machines and more particularly to the detecting of high tension in the individual yarn and identifying the yarn in which the high tension exists.
In yarn working machines such as tufting machines the existence of excessively high yarn tension will either break the yarn or produce a product which is defective. Various yarn detecting devices which stop the machine in case of yarn breakage or excessive tension are known in the art.
Tufting machines such as those used to produce tufted carpet may employ upward of 1,000 needles mounted for vertical reciprocation, each of which needles carries a separate individual yarn into cooperative relationship with a looper to produce the tufted pile. Due to various conditions such as creel snarl-ups, that is yarn snarling as it pulls off the creel cones, excessive tension in one or a few yarns may occur. The resulting defective carpeting produced may be quite expensive since detection may not occur until many yards of fabric have been produced. The prior art detectors such as those illustrated in U.S. Pat. Nos. 3,221,682; 3,221,683 and 3,764,773 have been directed toward devices which will detect the type yarn end and stop the machine so as to minimize the waste. These detectors do not however determine which particular yarn end has the excessive amount of tension. Thus the operator must search back to the creel to determine the troublesome yarn end. With a full size tufting machine having over 1,000 yarns this can be quite a difficult and time consuming operation.